Variable resistor with snap-on mounting



1955 M. B. ARISMAN ErAL VARIABLE RESISTOR WITH SNAP -ON MOUNTING 2Sheets-Sheet 1 Filed Feb. 3, 1954 Oct. 18, 1955' v ARlsMAN ETAL2,721,245

VARIABLE RESISTOR WITH SNAP-ON MOUNTING Filed Feb. 3 1954 ZSheets-Sheet2 jmdwgw Mar vm B. .Arzsman Arihur M. UazZy United States PatentVARIABLE RESISTOR WITH SNAP-0N MOUNTING Mervin B. Arisman, Elkhart, Ind,and Arthur M. Daily, Edwardsburg, Mich., asslgnors to Chicago TelephoneSupply Corporation, Elkhart, Ind., a corporation of Indiana ApplicationFebruary 3, 1954, Serial No. 407,912 2 Claims. (Cl. 201-55) Thisinvention relates to variable resistors of the type used in radio andtelevision receivers and has as its general purpose to provide animproved manner of fastening such controls to a mounting panel.

Heretofore the fastening of variable resistors and similar components ofradio and television receivers to the panels upon which they weremounted generally has been accomplished either by means of clamping nutsthreaded on a bushing in which the operating shaft was journaled, or byfastening ears or tabs extended forwardly from the control through holesin the mounting panel, and either twisted or bent over the front face ofthe panel. All of these past expedients, however, entailed an operationin addition to the placement of the control upon the panel. Either a nuthad to be applied and tightened, or the ears or tabs had to be twistedor bent over.

To obviate the need for such additional operations and thereby speed upthe assembly of variable resistors and similar components of radio andtelevision receivers with their mounting panels, it is the purpose andobject of this invention to provide a manner of attaching or fastening aradio or television receiver control or other component to its panelwhich may be truly characterized as a snap-on mounting capable of beingcompleted and rendered operative to firmly fasten the component onto thepanel, by the simple act of pressing the component against the panel.

Another object of this invention is to apply this snap-on mountingconcept to a variable resistor of type described in a way which does notincrease the number of parts or seriously affect present tooling. Tothis end it a further object of this invention to provide a snap-onmounting especially adapted for fastening variable resistors and thelike to their mounting panels in which the essential elements constituteone or more pairs of hooked fingers which engage behind the edges ofslot-like openings in the mounting panel into which the fingers areinserted as the control is" snapped into position, and which fingers areresilient so that they may be sprung as required to enable theirinsertion into slots which are shorter than the distance across thepoints of the hooks, to thus enable the hooks to be operatively engagedwith the panel.

One of the most important considerations in the mounting of variableresistors and similar controls which are adjusted by rotation of ashaft, is that the control be securely held against even the slightestrotational freedom so that the torque imposed upon the control as theshaft is turned will not cause the control to shift. In recognition ofthis requirement, it is another object of this invention to provide asnap-on fastening which inherently secures the control against anypossible rotational displacement.

With the above and other objects in view, which will appear as thedescription proceeds, this invention resides in the novel construction,combination and arrangement of parts substantially as hereinafterdescribed and more particularly defined by the appended claims, it beingunderstood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying. drawings illustrate two complete examples of thephysical embodiments of the invention constructed according to the bestmodes so far devised for the practical application of the principlesthereof, and in which:

Figure l is a side view of a variable resistor embodying one adaptationof this invention and illustrating the resistor mounted on a panel;

Figure 2 is a perspective view of the front end of the variable resistorshown in Figure 1, but detached from the panel;

Figure 3 is a fragmentary side view of a portion of the resistorillustrating the manner in which the attaching fingers are sprung out oftheir normal positions during attachment of the resistor to its mountingpanel;

Figure 4 is a front view of the mounting panel with the resistorpositioned thereon, the resistor being illustrated in dotted linesbehind the panel; and

Figure 5 is a perspective view similar to Figure 2 but illustrating aslightly modified embodiment of the invention.

Referring now particularly to the accompanying drawings, the numeral 5designates generally a variable resistor of the type used in radio andtelevision receivers, and which, as is customary, has itsinstrumentalities enclosed within a housing comprising a flat base 6 ofinsulating material, and a cup-shaped metal cover or shell 7 having theedge of its cylindrical side wall connected to the base. As is alsocustomary, a ground plate 8 overlying the front face of the base issecured in position by the assembly of the cover with the base, and anoperating shaft 9 passes through the base and the ground plate andprojects forwardly therefrom.

The snap-on mounting comprises a plurality of pairs of hooked springfingers 10. In that form of the invention shown in Figures 1 through 4inclusive, these hooked fingers are integral with and are bent forwardlyfrom the ground plate 8. In the modification shown in Figure 5 thecorresponding spring fingers 10' are an integral part of the side wallof the cover or shell 7 and project forwardly from its marginal edge. Ineach instance the fingers are spaced a substantial distance radially outfrom the axis of the control. The purpose and significance of thisspacing will appear hereinafter.

To assure the desired stability in the mounting, it is preferable toemploy three pairs or sets of spring fingers two of them diametricallyopposite one another, and the third diametrically opposite the terminals11 of the control.

The spring fingers of each pair are disposed in edgewise spacedrelationship with their hooks 14 facing in 0pposite directionssubstantially perpendicular to a line extending from the axis of thecontrol and passing between the adjacent back edges of the fingers. Thisdisposition of the spring fingers enables them to be sprung toward Peach other but nevertheless gives them sufiicient strength to stronglyresist such deformation. Each pair of fingers snaps into a slot oropening 12 in the mounting panel as the control is applied thereto. Theopposite ends or edges 13 of the slots 12 are spaced apart a distanceless than the distance across the points of the hooks 14 so that in theattachment of the control to the panel the fingers must be sprungtowards each other. This necessary lateral edgewise deflection of thespring fingers is facilitated by cam surfaces 17 on the outer side edgesof the fingers, which of course cooperate with the adjacent ends oredges 13 of the slots or openings 12, as shown in Figure 3.

Locating feet or shoulders 16 face the undersides 15 of the hooks on thespring fingers to engage the adjacent side of the panel and space thecontrol a definite distance therefrom. This distance is sufficient toprovide adequate electrical clearance between the panel and theterminals of the control. The locating shoulders 16 are preferablyformed as a part of the spring fingers by giving the fingers the offsetshape shown, and all of the locating shoulders lie on a common planeperpendicular to the axis of the control shaft when the fingers are intheir normal free positions. Attention is directed to the fact that theshape of the fingers which produces the locating feet or shoulders 16,leaves the fingers with substantially the same width for their entirelength so that the fingers possess the desired resilience.

' It is important to note that the undersides 15 of the hooks are notparallel to the locating feet or shoulders 16, out define a divergingangle with respect thereto. In other words, the undersides 15' arecloser to the plane of the shoulders 16 at their inner ends than attheir outer ends. It is also important to observe that the averagespacing between the undersides 15 of the hooks and the locatingshoulders 16 is substantially equal to the thickness of the panel.Hence, the wedging action of the inclined undersides 15' draws thelocating shoulders or feet 16 firmly against the adjacent side of thepanel.

The significance of the locations of the fingers a substantial distanceradially out from the axis of the control, and their paired arrangementas described, lies in the fact that this disposition of the fingersaffords the greatest assurance against even the slightest free rotationof the control about its axis, or chuck as such looseness in themounting is called in the industry. Any possible play which might permitchuc as the control is adjusted, is taken up by the spring tension underwhich the fingers are maintained by their wedge-like engagement with theopposite ends of their respective panel slots or openings.

From the foregoing description taken in connection with the accompanyingdrawings, it will be readily apparent that this invention provides anextremely simple, but highly effective, snap-On mounting, which isexceptionally well adapted for use with variable resistors, where it isimportant that the control be firmly held against even the slightestpossible rotation about its axis, but of course may be employed toattach other components of radio and television receivers to theirrespective mounting panels.

What we claim as our invention is:

1. In a variable resistor of the type which is adjusted by rotation of acontrol shaft so that during adjustment of the resistor torque isimposed upon the resistor, said variable resistor having a housing withspaced end walls through one of which the control shaft passes, asnap-on fastening for the resistor comprising: a stamped metal platesecured to the housing in overlying relation to one of its end walls;diametrically opposite radially outwardly projecting arms on said plate,said arms being bifurcated to provide a pair of diverging fingers oneach arm having their inner portions lying in the plane of said plateand their outer end portions bent up substantially perpendicularly tothe plane of the plate and projecting therefrom, the bent-up portions ofthe fingers of each arm being disposed in edgewise spaced relation andbeing coplanar; outwardly facing locating shoulders on said bent-upportions of the fingers lying in a common plane parallel to and spaced ashort distance outwardly of the plane of said plate; and hook means onthe fingers outwardly of the shoulders to engage over the edges of holesin a panel upon insertion of the fingers into said holes, said hookmeans coacting with the panel to clamp the shoulders firmly against thepanel and firmly hold the resistor against turning about the axis of itscontrol shaft, engagement of the fingers into the holes in the panel toengage the hook means therewith entailing substantial fiexure of thefingers of each pair toward one another.

2. In a variable resistor of the type which is adjusted by rotation of acontrol shaft so that during adjustment of the resistor torque isimposed upon the resistor, said variable resistor having a housing withspaced end walls through one of which the control shaft passes, asnap-on fastening for the resistor comprising: a stamped metal platesecured to the housing in overlying relation to one of its end walls;diametrically opposite radially outwardly projecting arms on said plate,said arms being bifurcated to provide a pair of diverging fingers oneach arm having their inner portions lying in the plane of said plateand their outer end portions bent up substantially perpendicularly tothe plane of the plate and projecting therefrom the bent up portions ofthe fingers on each arm being disposed in edgewise spaced relation andbeing coplanar, and having an edgewise offset stepped shape with theremote edges of their inner portions which lie adjacent to said platespaced farther apart than the remote edges of their outer end portions,the steps formed by said offset providing widely spaced outwardly facinglocating shoulders lying in a common plane parallel to but spaced ashort distance outwardly of said plate to seat upon a panel upon whichthe resistor is to be mounted, the outer end portions of said fingershaving notches in their remote edges directly adjacent to the locatingshoulders, and the edges of said notches which face towards theshoulders being inclined at a diverging angle to the shoulders so thatupon projection of the fingers through slots in a panel which isslightly thicker than the minimum distance between the locatingshoulders and the opposite inclined edges of the notches, said shouldersare drawn firmly against the panel and the resistor is firmly heldagainst turning about the axis of its control shaft, providing the slotsare no shorter than the normal free distance from the bottom of thenotch in one finger to the bottom of the notch in the other finger.

References Cited in the file of this patent UNITED STATES PATENTS

